It was corydoras for me. Before keeping cories, I avoided them b/c I saw them as derpy, chunky fish that hardly moved. A friend broke down his aquarium so I took in his fish--a school of peppered cories included. Welp, turns out I'm a fiend for derpy, chunky fish and to my surprise they're real active. I'll watch them school, go up/down the glass, and ram their faces into food. I've since purchased 4 other species. Love them cories